1. Field of the Invention
The present invention relates to a carrier, and more particularly, to a carrier that automatically travels on a pathway.
2. Description of the Related Art
In the related art, a carrier that travels on a pathway is known. Such a carrier includes, for example, an environmental map storage, a distance measuring sensor, and a control unit.
The environmental map storage stores an environmental map that indicates an area where structures constituting a pathway are present and an area where the structures are not present. The distance measuring sensor is provided, for example, in front of the carrier and scans laser light, for example, over a range of 190 degrees in front of the carrier. Thus, the distance measuring sensor obtains positional data of reflectors based on reflected light from the structures constituting the pathway and obtains pathway information. The control unit calculates a position of the carrier by matching the obtained pathway information to the environmental map.
There is known a carrier that calculates a position of a carrier main body by detecting reflecting plates attached to rack columns, in particular, for the purpose of obtaining an accurate position of the carrier (e.g., refer to JP 2013-161399 A).
When an approximate line as the pathway information is matched to a line segment of the environmental map in the carrier described above, geometrical characteristics (e.g., corners) of both data are overlapped with each other so that the relative position and orientation of the both data are calculated. Therefore, when three columns are arranged, for example, in a straight line in the scanning area of the laser light, it is difficult to identify the position of the carrier.